When the elite distance runners Sara and Ryan Hall adopted four sisters from Ethiopia in October 2015, it was the start of a year of seismic changes for them.

Ryan, 34, the fastest American distance runner ever, announced his retirement in January, and began zealously lifting weights, replenishing testosterone levels diminished by years of 100-mile weeks. Sara, 33, will race in the professional field of the New York City Marathon on Sunday, her third in a year.

Their daughters have not only adapted to life in the United States but to life as children of some of the best runners in the world. The Halls, who met as All-Americans at Stanford, say over all their personal and professional transitions this year have intersected neatly, and building their new family has been as rewarding as any race.

“I keep saying to Ryan I can’t believe how smooth this has been, they act like biological kids would, and I feel really thankful,” said Sara. “I think with adoption, you hear a lot of the negative stories about kids who have been through a lot and don’t adapt well, which is good because you need to go in with eyes wide open, but sometimes you don’t hear enough about the good things.”

It was an integration of cultures that was eased in large part through running. Although the girls were not runners — they had been confined to the grounds of their Ethiopian orphanage for most of their lives — they had watched Ethiopia’s celebrity distance runners on television. And many of the Halls’s training partners were Ethiopian. At the Mammoth Lakes training camp in California, they lived down the street from the American Olympian Meb Keflezighi, who was born in Eritrea, which borders Ethiopia, and whose family had the Halls over for dinners of traditional injera flatbread, spicy stews and tea.

They trained in Ethiopia as well. Once the Halls focused on adopting, they spent roughly five months over a span of nine months in the country, running with their Ethiopian friends and learning the Amharic language. When they met their future children, they spent a week visiting the orphanage in the Ethiopian capital before asking the girls if they would like to be adopted and come home with them. (The family plans to spend the girls’ Christmas break there next month, and they are considering moving to Ethiopia in the future to pursue work with their charity, the Steps Foundation, which seeks to reduce global poverty by promoting health.)

Now their daughter Lily, 6, is in kindergarten; Jasmine, 8, is in third grade; Mia, 12, is in sixth grade; and Hana, 16, is a high school freshman, all in their local public schools. (Because they don’t have birth certificates, the girls’ ages were initially estimates. Dental X-rays now suggest that some of the girls are younger than originally thought, so the Halls have adjusted their birth dates accordingly.)

Though the Halls’s Northern California community of Redding is small, they know at least 30 other Ethiopians in the area, including four Ethiopian children adopted by another family four years ago who are now good friends of the Halls’s children. The families shared the same social worker to help with the adoptions.

The Halls say their strong Christian faith helps bond them. The children grew up in the Ethiopian Christian tradition and have integrated into the Halls’s charismatic evangelical church.

“They love our church and are thriving there,” said Sara. “Faith is a huge part of every aspect of life, like getting over trauma, and we use our faith in that process.”

And the girls have embraced their parents’ athletic lifestyle. After watching the Olympics with her family this summer, Lily decided she wanted to start gymnastics, while Jasmine is playing soccer, just as Sara did as a child. The oldest two girls have both started running; when they ran track together last spring their retired Olympian father coached the team. They had a photo finish in the mile.

The Halls often watch live feeds of races with some of their top East African competitors and their daughters react like it’s the Super Bowl, picking out the runners from their home country. Sara showed them a picture of her racing with Tirunesh Dibaba, the Ethiopian outdoor 5,000-meter world-record holder, inspiring respectful acknowledgment from her children.

“I think they have a better attention span than a typical American child,” Sara said. “They can watch an entire 10K from start to finish and stay riveted.”

“When we told them what we do, they’d say, ‘That’s not a real job, you have to be writing stuff in an office,’” Sara said, though the girls relish the free foods that come from their parents’ eclectic sponsors. Their father prepares pancakes laced with Muscle Milk every morning, and packages of sponsor-sent Alaskan salmon are a lunchbox favorite. “My 8-year-old will pray, ‘Please keep mom strong, not like dad, so she can keep running, and we can keep getting free fish’” Sara said.

Sara makes them the Ethiopian food they grew up with as well, infusing it with the healthy cooking approaches she’s taught herself to fuel her training. “I make doro, or sometimes it’s just the shiro, or split peas and lentils and kale,” she said. “My daughter told me I should open an Ethiopian restaurant, and I thought it was such an exciting compliment.”

They now speak in both English and Amharic; the girls call Ryan “Poppy-o,” and in addition to “Mommy” they call Sara “Mammu,” or “Ananti,” meaning Mom in Amharic. Just as the couple continues to teach their children English, their daughters help them brush up on Amharic — with the help of the new Amharic edition of Google Translate.

There are still some adjustments to work through. “My daughter will use 10 paper towels to pick up a stray dog hair,” Sara said. “But she’s never had paper towels, and she doesn’t understand about the environment. There are so many layers you forget they don’t know yet.”

Meanwhile, Ryan has begun running again, gradually building up his speed to the point where he can keep pace with Sara. He helped coach her before the Olympic marathon trials and paced her or biked with her in tempo runs this summer.

“Ryan and I are both really driven, and that’s something we really want for our kids,” said Sara. “But we expect the initiative to come from them. We don’t tell them to run; if they want to run, we wait for them to say they want to. But of course we’ll support them, we’ll be out there on the bike.”

Now the Halls’s oldest daughter, Hana, is hoping to make it to her first state meet with her new team, where she will race on the California course where her parents first established themselves.

“Some of my best memories are the team aspect of cross country and going to the meets, it is so much fun,” said Sara. “I’m excited to be a part of that again, through them.”